Not long ago, the Time School reported that a "new physiological age clock" was jointly created by Professor Han Jingdong, Professor Kennedy Brian and many other first-class anti-aging scholars at home and abroad[1].
The new clock is made up of nine major organ systems, one of which is an important component of kidney aging.
Why does a urinary organ that is in charge of the "sewer" become an important determinant of the level of aging in the whole body?
From the perspective of clinical geriatrics, our article will provide you with a comprehensive analysis of the causes of kidney aging, the manifestations and evaluation methods of kidney aging, the significance of kidney aging to systemic aging, and the most critical - whether it is possible to delay kidney aging.
50 smaller, 70 halved,
Morphological changes, function decreases
The effect of aging on the kidneys is first reflected in the structure of the naked eye:
From the age of 30 to age 80, the kidney volume decreases significantly by 20% to 25%, and this decline becomes more pronounced after the age of 50 [2].
Zoomed in under the microscope, the essence of the kidney is composed of independent renal units, and there are about 1 million kidney units in one kidney: the blood vessels are coiled into glomeruli, and waste and excess water are filtered out of the blood during the cycle rotation, which is called the original urine; the original urine is then flowed in the renal tubules, reprocessed and concentrated, and finally becomes a collection of urine and waits to be excreted. A glomerular and a corresponding tubule form a renal unit, which is the most basic structural and functional unit of the kidney.
Under the influence of aging, a series of microscopic changes such as arteriosclerosis, glomerular sclerosis, compensatory hypertrophy of residual glomeruli, fibrosis, and tubular atrophy occur in the renal units, which directly cause the overall function of the renal units to decline. A study of a sample of kidney transplant donors found that donors aged 70–75 had about 50 percent fewer functional renal units of their kidneys than donors aged 18–29 [3]. The "employees" who work have aged and reduced their staff, and the overall work efficiency will naturally drop sharply.
In addition, older adults are more likely to develop kidney cysts than younger people, and are usually more numerous and larger [4]; adipose tissue and interstitial fibrosis replace the residual functioning renal parenchyma during aging[2], and these morphological changes further lead to a decline in kidney function.
Note: Manifestations of renal senescence (translated from [2])
The most basic physiological function of the kidneys is the excretion of metabolic waste. How to measure the excretion function of the kidneys, we need an indicator called glomerular filtration rate (GFR), the actual GFR is very complex to measure, so in practical applications, by calculating the concentration of some representative substances in the blood, indirectly calculate the efficiency of their removal by the kidneys, to get an estimated GFR (eGFR).
The representative substance with the highest frequency when calculating eGFR is creatinine (Cr), a metabolite of muscle, supplemented by two other metabolites, urea nitrogen (BUN) and uric acid (UA), as evidence of decreased renal function, which together constitute the most basic "renal function test" in clinical tests.
The "new physiological age clock" mentioned at the beginning of the article, which selects 3 indicators to evaluate kidney function, is also directly applied to this most basic package.
Holding a kidney of the old body,
The key problem is not just urinary
The function of the kidneys in excreting metabolic waste products through urine (embodied in GFR) gradually declines with age, and this phenomenon is currently generally considered to be a physiological manifestation of kidney aging [5].
This decline in function is generally harmless to healthy older people, and kidney aging itself does not cause kidney disease, and does not even affect the elderly to become donors of kidney transplants, donating organs to young people [6].
As we all know, the kidney is a "silent organ", and if you get sick, you will not "cry out for pain" in time, and even in the early stage of kidney failure, the human body often does not feel obvious discomfort. Diagnosis of chronic kidney disease (CKD) depends only on renal function tests. However, kidney function declines with age, and the value of diagnostic criteria does not change with it, which can easily cause the elderly to be misdiagnosed as "chronic kidney disease (CKD)" [7].
Patients with severe chronic kidney disease (CKD) need to undergo regular hemodialysis "blood washing" to save their lives
In addition, eGFR calculated solely from serum creatinine is not perfect, and elevated creatinine levels after strenuous exercise may result in small eGFR, and decreased creatinine levels may result in a decrease in muscle mass in older adults [8].
In recent years, scholars have proposed that the introduction of cystatin C, a more robust indicator, can be used to calculate eGFR, which can make the estimated kidney function more accurate [9]. This indicator is also included in the Chronophilim Blood Test Kit to help users more accurately assess their kidney function. It can detect 50 indicators of the human body at the same time, and understand the aging process and disease risk from 5 levels such as inflammation, organ and metabolism. You can send [QE Detection] to the assistant for details, assistant: timepie10. After testing, Time Pai will propose mature and effective interventions at every level to help you block future health risks.
Accurate eGFR calculation of the corresponding age can better detect the signs of kidney disease from the normal aging process. Here is an online tool to assess the current risk of chronic kidney disease (CKD) based on the serum creatinine/+ cystatin C index and automatically recommend visits and renal function monitoring: https://www.kidney.org/professionals/kdoqi/gfr_calculator
In summary, in the aging process, if we only look at the kidney as a urinary organ, it does not get sick because of aging, and we do not need to worry too much about its health. However, kidney aging leads to a decrease in renal function reserves, which greatly reduces the kidney's ability to resist risk attacks, and we still need to pay attention to the following points:
1. Middle-aged and elderly people need to pay attention to monitoring blood pressure and blood sugar, standardize antihypertensive and hypoglycemic therapy, try to avoid the use of nephrotoxic drugs, the elderly are more likely to encounter chronic kidney disease (CKD), and often progress faster;
2. When the elderly face trauma, infection, acute disease attacks, etc., they need to seek medical attention in time to avoid acute kidney injury (AKI);
3. The elderly need to follow the doctor's instructions to adjust the dosage of drugs metabolized by the kidneys.
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It is worth noting that the kidney is not just a simple urinary organ, it also has a side business that cannot be ignored - the kidney is an important endocrine organ. Among the many hormones secreted by the kidneys, two are most closely related to systemic aging, and it is worth discussing together:
25-(OH)2-D3(calcitriol):
As the most biologically active form of vitamin D in the body, vitamin D needs two hydroxylations to become it, and the most important one hydroxylastension requires 1α-hydroxylase secreted by the kidneys to assist in the completion.
As the kidneys age and the kidneys age, the body's ability to hydroxylify vitamin D gradually decreases [10]. The role of vitamin D in human bone health, immunity, cardiovascular health, cancer prevention, and anti-aging is not necessary to repeat.
Middle-aged and elderly people, especially middle-aged and elderly people with significant decline in renal function, should pay more attention to vitamin D supplementation and need to directly supplement the active form of vitamin D (calcitriol).
Klotho：
We have introduced readers to the gene of "mastering the lifespan of mortals" - Klotho, who was given the name of "Three Goddesses of Destiny". The Klotho gene expresses the Klotho protein, which exerts anti-aging effects such as antioxidant, anti-inflammatory, anti-cellular aging, anti-stem cell depletion and promotion of autophagy.
This expression process is done primarily in the kidneys, where renal aging reduces Klotho production with age [11].
anti-aging intervention,
Or the optimal solution of "kidney tonic"
If you ask a professional doctor, how do healthy people protect their kidneys? The answer you can get is definitely "drink more water". Ingesting as much water as possible within a reasonable range is more conducive to kidney functioning, excretion of waste products, and is beneficial to both kidney and whole body health.
Unfortunately, drinking more water is not very helpful in delaying kidney aging.
Similarly, treatments used to save renal function and prevent disease progression in patients with early kidney disease—such as protein-restricted diets and ACE/ARB drugs—do not combat normal renal aging [12].
Looking at the existing research, the means to combat kidney aging are still only familiar with these systematic anti-aging methods, and the author ranks them according to the current accessibility:
Anti-aging substances:
NAD+ is a dazzling star in the fight against kidney aging, through NMN and other NAD+ precursor substances to enhance the level of NAD+, for enhancing the kidney resistance, prevention and treatment of aging-related kidney diseases, has been a lot of verification in animal models, is one of the research hotspots of NAD+ substances [13].
Senolytics：
Senescent cells tend to accumulate in the kidneys during the natural aging process, which has a direct causal relationship with age-related decline in kidney function. Interventions for senescent cells, such as senescent cell lysis drugs (Senolytics), may have important therapeutic potential for alleviating age-related renal dysfunction, improving renal disease outcomes, and ensuring successful kidney transplantation [14].
Intestinal microbiome remodeling:
The "novel physiological age clock" mentioned at the beginning of the article shows a negative correlation between the physiological age of the kidneys and the aging rate of the gut microbiome through comparison [1]. Thus shaping a good nest of gut microbes may help delay kidney aging.
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Anti-aging interventions such as reducing telomere depletion, anti-chronic inflammation, and plasma exchange have also been shown to alleviate kidney aging; exercise is also effective in delaying age-related decline in kidney function.
Seeing this, I don't know if you will start to think about a question: whether it is the fat aging that was introduced to you some time ago, or the kidney aging that is discussed together today, the aging of different organ tissues will always affect the whole body; although there are slight differences, the effective intervention means always include the familiar "old things"?
We always want to summarize all aging-related phenomena from a systematic point of view, and the continuous research may one day be able to glimpse the whole picture, and the artifacts against aging and many related diseases may only be the same.
Before finding the "only solution", it is enough to do a good job of anti-aging efforts that can be done.
—— TIMEPIE ——
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